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arXiv · 1403.6856

Measuring the superconducting coherence length in thin films using a two-coil experiment

John Draskovic·Thomas R. Lemberger·Brian Peters·Fengyuan Yang·Jaseung Ku·Alexey Bezryadin·Song Wang
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Abstract

We present measurements of the superconducting coherence length ξ in thin (d < 100 Å) films of MoGe alloy and Nb using a combination of linear and nonlinear mutual inductance techniques. As the alternating current in the drive coil is increased at fixed temperature, we see a crossover from linear to nonlinear coupling to the pickup coil, consistent with the unbinding of vortex-antivortex pairs as the peak pair momentum nears \hbar\/ξ and the unbinding barrier vanishes. We compare measurements of ξ made by this mutual inductance technique to values determined from the films' upper critical fields, thereby confirming the applicability of a recent calculation of the upper limit on a vortex-free state in our experiment.

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John Draskovic, Thomas R. Lemberger, Brian Peters, Fengyuan Yang, Jaseung Ku, Alexey Bezryadin, Song Wang. 2014-03-26. Measuring the superconducting coherence length in thin films using a two-coil experiment. https://arxiv.org/abs/1403.6856

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